In Iten, a small town perched on a dramatic escarpment 2,400 metres above sea level in Kenya’s Rift Valley, the local St Patrick’s High School used to honour any former pupils who won a world or Olympic athletics medal by planting a tree in their name in the school grounds.

The ritual was modified some years ago when the groundsman complained that the school were being turned into a forest, and now the achievements of its world-beating alumni are marked by rather more modest shrubs.

The horticultural explosion is the work of one remarkable man, Brother Colm O’Connell, who arrived at the school on a three-year contract as a geography teacher in 1976 but with no knowledge of athletics beyond a passing interest in the sport.

Thirty-five years later, he is still there and acknowledged as the world’s most successful coach of endurance running, having nurtured four Olympic gold medallists and 25 world champions, the latest being 800 metres world record-holder David Rudisha.

Astonishingly, 10 of the 17 Kenyan medallists at last summer’s World Championships in Daegu were products of his coaching stable and the domination of his runners is certain to continue at this summer’s London Olympics.

Not that he will be there to witness it. O’Connell, a genial Irish lay Patrician brother, has never been to an Olympic Games or World Championships in all his decades of coaching and has no plans to travel to London.

“It’s not a priority for me,” he said. “I grew up not travelling with the Kenyan team. Those were the days when very few people went with the team. I’ll just stick to watching it on TV.”

His coaching career began shortly after his arrival at St Patrick’s, where a fledgling athletics programme was being overseen by Peter Foster, brother of British athlete turned BBC commentator, Brendan.

“Peter had one more year to go on his contract and I think he felt at the time that I would be a likely candidate to keep the programme that he had started,” says O’Connell. “So he invited me to the local track to take my first lessons in coaching and a year later I became the coach.

“Most of my coaching I learned from the athletes – watching them training, talking to them, seeing what worked – very basic training methods. I also read a few books about coaching and talked to a few fellow coaches who I met at competitions. That was my only experience. It wasn’t until about five years later and I began to learn more technically about the sport.”

Despite his technical research, O’Connell insists there is nothing scientific about his methods and is scornful of the new-fangled gadgetry that is part and parcel of modern-day coaching.

There are no underwater treadmills, ice baths or even heart monitors at St Patrick’s. His success, he says, is down to the sheer hard graft of his athletes and the desire of his younger pupils to emulate the triumphs of the world-beating athletes they see every day pounding out the mileage on Iten’s rocky trails.

“All sorts of research has been done in order to isolate a specific reason for the success of Kenyan athletes,” he says. “All sorts of experiments on things like physiology, climate, altitude, diet, genetics. But nobody seems to have come up with a satisfactory conclusion.

“I think myself it’s partly due to the running culture in the area that has been created. It’s the fact that when the sport became professional, so many athletes came to this area to train, and then the kids could see their role models and successful athletes around the paths and roadways of Iten.”

O’Connell’s successes extend beyond St Patrick’s, having set up Kenya’s first ever high-altitude training centre – initially just for female runners but now expanded to include other male, non-St Patrick’s athletes like Rudisha. His fame means talented young runners from all over the country now beat a path is to his door.

His achievements have also spawned more than a hundred similar training camps, including the Iten centre run by four-time world champion Lorna Kiplagat that is currently the residence of 22 British endurance runners.

The GB camp is part-funded by the London Marathon and last Friday race officials were in town to inspect the facilities and host a media conference to announce the star Kenyan athletes who will be competing in London in April.

The cast list was a reminder of just how dominant Kenya has become in global athletics, with those on the top table including marathon world record-holder Patrick Makau, defending London champion Emmanuel Mutai, three-time London champion Martin Lel and two-time world champion Abel Kirui.

Appropriately, O’Connell, the man who began the Kenyan success story, was a special guest.

“It seems like a dream now,” he says. “When I see all the people here in Iten, I think to myself, ‘Is that really what I started all those years ago?’”